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Agonist-independent activity of G-protein-coupled receptor, also referred to as constitutive activity, is a well-documented phenomenon and has been reported recently for both the histamine H(1) and H(2) receptors. Using SK-N-MC cell lines stably expressing the human and rat H(3) receptors at physiological receptor densities (500-600 fmol/mg of protein), we(More)
Recent immunocytochemical studies have demonstrated the existence of histaminergic neurons in the brain, which are concentrated in the tuberomammillary nucleus of the posterior hypothalamus, and which project efferent fibers to almost all parts of the brain. Three subtypes of histamine receptors are widely distributed in the brain, not only on neurons but(More)
In this study, we continue our efforts toward the development of potent and highly selective histamine H(3) receptor agonists. We introduced various alkyl or aryl alkyl groups on the piperidine nitrogen of the known H(3)/H(4) agonist immepip and its analogues (1-3a). We observed that N-methyl-substituted immepip (methimepip) exhibits high affinity and(More)
The contents of histamine in various tissues of mutant mice deficient in mast cells (W/Wv) and in congenic normal mice (+/+) were determined by high-performance liquid chromatography and were compared. In spite of the absence of mast cells in W/Wv mice, the histamine content of their whole bodies was about 5-10% of that of +/+ mice. The skin, heart and(More)
Modafinil, (RS)-2-(Diphenylmethylsulfinyl)acetamide, is a well known wake promoting drug used for the treatment of narcolepsy. We investigated the effect of modafinil on the hypothalamic histamine release in the anesthetized rat using in vivo microdialysis. Modafinil (150 mg/kg, i.p.) increased histamine release by 150% of the basal release. The(More)
One hour after the intraperitoneal (i.p.) injection of FMH (200 mg/kg), locomotor activity and rearing were statistically reduced, by 3 hours later, only the locomotor activity was reduced in rats. The i.p. injection of FMH (100 and 200 mg/kg) had no effects on motor incoordination, blood pressure, heart rate and tetrabenazine-induced ptosis in rats. One(More)
Hochu-ekki-to is a traditional herbal (Kampo) medicine that has been shown to be effective for patients with Kikyo (delicate, easily fatigable, or hypersensitive) constitution. Previous case reports have suggested that this herbal drug was effective for a certain subgroup of patients with atopic dermatitis (AD). We aimed to evaluate the efficacy and safety(More)
A highly sensitive and specific method was developed for the determination of histamine in biological materials by high-performance liquid chromatography with a cation exchanger and an automated Shore's fluorometric detection system. Since substances causing interference in Shore's o-phthalaldehyde method, such as ammonia, histidine, spermine and(More)
The distribution of histamine-immunoreactivity in the carbodiimide-fixed brain and visual system of the cockroach was revealed immunocytochemically with an antiserum against histamine (HA). Histamine levels were measured with high-pressure liquid chromatography. The results show a widespread distribution of histamine-containing somata and fibers in the(More)